Realizing Formation and Decomposition of Li2O2 on Its Own Surface with a Highly Dispersed Catalyst for High Round-Trip Efficiency Li-O2 Batteries

Abstract

The rapid and effective formation and decomposition of Li₂O₂ during cycling is crucial to solve the problems associated with the practical limitation of lithium-oxygen (Li-O₂) batteries. In this work, a highly dispersed electrocatalyst with Ru nanoclusters inside the special organic molecular cage (RuNCs@RCC3) through a reverse double-solvent method for Li-O₂ batteries has been proposed for the first time. This RuNCs@RCC3 shows an effective catalyst enabling reversible formation and decomposition of the Li₂O₂ at the interface between the Li₂O₂ and the liquid electrolyte, rather than the sluggish solid-solid interface reactions on commonly used solid catalysts. As a result, the Li-O₂ cells with RuNCs@RCC3 show enhanced electrochemical performance, including low overpotential (310 mV at a current density of 100 mA g^-1), high specific capacity (15,068 mAh g^-1), good rate capability (1,800 mAh g^-1 at a current density of 2.8 A g^-1), and especially superior cycle stability up to 470 cycles.